Amount due does not add up
The amount due (BT-115) must equal: gross amount (BT-112) minus amount already paid (BT-113) plus rounding (BT-114).
What to do now
Who has to fix this?
The issuer or their invoicing software has to fix this. Arithmetic violations almost always point to a rounding or mapping error when the XML is generated, not to a typing mistake.
Where this rule comes from
The BR-CO rules of EN 16931 hold the arithmetic together: line totals, allowances and charges, the VAT breakdown and the grand totals must add up exactly — to the cent. They also define which fields may only appear together.
- Rule ID
- BR-CO-16
- Rule set
- Calculations & dependencies
- Checked for
- XRechnung, ZUGFeRD, Factur-X, Peppol BIS and other EN 16931 formats
- Consequence of a violation
- The invoice is considered non-compliant with the standard and is automatically rejected by many recipients.
Does BR-CO-16 occur in your invoice?
Upload the XRechnung or the ZUGFeRD/Factur-X PDF – the validator shows every violation with the same explanation as here. Free, no login, nothing stored.
Validate your invoice nowGeneral information, not tax or legal advice. As of October 2026. Validation rules: CEN/TC 434 (EN 16931, EUPL 1.2), KoSIT (XRechnung, Apache 2.0), FNFE-MPE/FeRD (Factur-X/ZUGFeRD, Apache 2.0), OpenPeppol AISBL (Peppol BIS), ANAF (CIUS-RO). Explanations: Billvox. Licence notices